This study focuses on Durban's Grey Street mosque, built by Indian Memon migrants in 1880. This review of the first half-century of the mosque's existence underlines the important social role of mosques, and also questions the notion of homogeneous Muslim community. While the mosque was the most visible symbol of Muslim identity in Natal, it was also a site of contestation, reflecting the class, language, caste and ethnic divisions among Muslims in a diasporic situation. Mosques were built along class and ethnic lines and dominated by traders. As Muslim society matured, there were challenges to the leadership of non-clerical traders who did not tolerate challenges to their authority. Opposition sometimes centred on Imams who commanded the allegiance of the congregation. Mosques did not have an independent life but reflected the prevailing power structures in Muslim society. While outsiders believed that ethnic diversity was subsumed by a unitary Muslim mass, Muslims comprised a community of communities, and the building and management of mosques underlined this fact.